The present invention relates to an apparatus for the assisting starting operation of an internal combustion engine provided with a carburetor or fuel injection device.
As is well known, the viscosity and specific weight of fuel supplied to an internal combustion engine decrease and the evaporation of the fuel is promoted as the fuel temperature increases. Thus, in an engine whose carburetor or fuel injection device has been adjusted in the unheated condition of the engine, the suction air-fuel mixture of the engine tends to be enriched as the engine temperature and hence the fuel temperature increases. Further, as the air temperature in the engine room or ambient air temperature becomes excessively high, the charging efficiency of the engine is decreased by the decreased specific weight of the fuel, by which also the mixture is enriched.
In order to improve the starting characteristic of the engine, the mixture is conventionally enriched during the starting operation when a suction air throttle valve is fully closed. Thus, at the time of the so-called hot restarting of the engine shortly after the engine has been stopped, the mixture is excessively enriched resulting in an incomplete combustion, and the starting operation cannot be effected easily.
Accordingly, it has been a conventional practice to open the throttle valve by depressing an accelerator pedal so as to avoid the excessively enriched condition at the time of a hot restarting operation. But, the enriched condition cannot always be avoided since such an operation is difficult to control properly and requires the driver's dexterity. Further, it is known to provide the air cleaner of a carburetor-equipped engine with an idling compensating device by which, however, effective and sufficient compensation cannot be achieved.